Integrated circuits are made possible by processes which produce intricately patterned material layers on substrate surfaces. Producing patterned material on a substrate requires controlled methods for removal of exposed material. Chemical etching is used for a variety of purposes including transferring a pattern in photoresist into underlying layers, thinning layers, or thinning lateral dimensions of features already present on the surface. Often it is desirable to have an etch process that etches one material faster than another facilitating, for example, a pattern transfer process. Such an etch process is said to be selective to the first material. As a result of the diversity of materials, circuits, and processes, etch processes have been developed with a selectivity towards a variety of materials.
Dry etches produced in local plasmas formed within the substrate processing region can penetrate more constrained trenches and exhibit less deformation of delicate remaining structures. However, as integrated circuit technology continues to scale down in size, the equipment that delivers the precursors can impact the uniformity and quality of the precursors and plasma species used, and the formation and profile of the plasma may also affect the quality of film deposition and etching.
Thus, there is a need for improved system components that can be used in plasma environments effectively to provide improved control over plasma and plasma characteristics. These and other needs are addressed by the present technology.